This study is an attempt to investigate prevalence of positive organizational behavior in the organizations in the service sector of Pakistan. We tested effects of organization based self-esteem, role stressors (role conflict, role overload and role ambiguity), leader-member exchange and perceived organizational support on positive organizational behavior as well as mediation of organization-based-self-esteem in this regard. Moreover, moderation of global self-esteem was also estimated in relationship between organization based self-esteem and positive organizational behavior. Data from 250 respondents from three service sectors of Pakistan (bank, hotel and education) was collected through mail survey and using stratified random sampling technique. Data analysis on the usable 215 questionnaires was made by using hierarchical multiple regression. Significant direct and indirect results through mediation of organization based self-esteem were found only for leader-member exchange, perceived organizational support and role ambiguity. Nevertheless, global self-esteem was not found to moderate the relationship of organization base self-esteem and positive organizational behavior. Implications and future research recommendations are also given.